For the last few weeks my blazer appears to be guzzling fuel....also the gas gauge is moving up and down more than usual....this morning the blazer started up just fine, then on my way home from work, after a brief stop, in which the engine was off, my blazer would not restart....had to have it towed home...anyone have any idea what it could be?...I am an amateur mechanic and need some advice as to how to proceed from here....I think it could be a fuel pump, not sure though....the tow truck driver said that if you hit the fuel tank with a mallet then it would start the blazer, he went ahead and hit it, and the fuel pump, just a bit ........it started up, but sounds really rough and I don't know if it will start up again without doing that...so now what?
Thanks for any helpful advice...

 

If a hit on the fuel pump gets it going then a fuel pump is in order. The reason it runs rough is the pump is more then likley not running at a constant speed when it does run.